// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/download/base_file.h"

#include <stddef.h>
#include <stdint.h>
#include <utility>

#include "base/files/file.h"
#include "base/files/file_util.h"
#include "base/files/scoped_temp_dir.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/strings/string_number_conversions.h"
#include "base/test/test_file_util.h"
#include "build/build_config.h"
#include "content/public/browser/download_interrupt_reasons.h"
#include "content/public/test/test_browser_thread_bundle.h"
#include "crypto/secure_hash.h"
#include "crypto/sha2.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace content {
namespace {

    const char kTestData1[] = "Let's write some data to the file!\n";
    const char kTestData2[] = "Writing more data.\n";
    const char kTestData3[] = "Final line.";
    const char kTestData4[] = "supercalifragilisticexpialidocious";
    const int kTestDataLength1 = arraysize(kTestData1) - 1;
    const int kTestDataLength2 = arraysize(kTestData2) - 1;
    const int kTestDataLength4 = arraysize(kTestData4) - 1;

    // SHA-256 hash of kTestData1 (excluding terminating NUL).
    const uint8_t kHashOfTestData1[] = {
        0x0b, 0x2d, 0x3f, 0x3f, 0x79, 0x43, 0xad, 0x64, 0xb8, 0x60, 0xdf,
        0x94, 0xd0, 0x5c, 0xb5, 0x6a, 0x8a, 0x97, 0xc6, 0xec, 0x57, 0x68,
        0xb5, 0xb7, 0x0b, 0x93, 0x0c, 0x5a, 0xa7, 0xfa, 0x9a, 0xde
    };

    // SHA-256 hash of kTestData1 ++ kTestData2 ++ kTestData3 (excluding terminating
    // NUL).
    const uint8_t kHashOfTestData1To3[] = {
        0xcb, 0xf6, 0x8b, 0xf1, 0x0f, 0x80, 0x03, 0xdb, 0x86, 0xb3, 0x13,
        0x43, 0xaf, 0xac, 0x8c, 0x71, 0x75, 0xbd, 0x03, 0xfb, 0x5f, 0xc9,
        0x05, 0x65, 0x0f, 0x8c, 0x80, 0xaf, 0x08, 0x74, 0x43, 0xa8
    };

} // namespace

class BaseFileTest : public testing::Test {
public:
    static const unsigned char kEmptySha256Hash[crypto::kSHA256Length];

    BaseFileTest()
        : expect_file_survives_(false)
        , expect_in_progress_(true)
        , expected_error_(DOWNLOAD_INTERRUPT_REASON_NONE)
    {
    }

    void SetUp() override
    {
        ASSERT_TRUE(temp_dir_.CreateUniqueTempDir());
        base_file_.reset(new BaseFile(net::NetLogWithSource()));
    }

    void TearDown() override
    {
        EXPECT_FALSE(base_file_->in_progress());
        if (!expected_error_) {
            EXPECT_EQ(static_cast<int64_t>(expected_data_.size()),
                base_file_->bytes_so_far());
        }

        base::FilePath full_path = base_file_->full_path();

        if (!expected_data_.empty() && !expected_error_) {
            // Make sure the data has been properly written to disk.
            std::string disk_data;
            EXPECT_TRUE(base::ReadFileToString(full_path, &disk_data));
            EXPECT_EQ(expected_data_, disk_data);
        }

        // Make sure the mock BrowserThread outlives the BaseFile to satisfy
        // thread checks inside it.
        base_file_.reset();

        EXPECT_EQ(expect_file_survives_, base::PathExists(full_path));
    }

    bool InitializeFile()
    {
        DownloadInterruptReason result = base_file_->Initialize(
            base::FilePath(), temp_dir_.GetPath(), base::File(), 0, std::string(),
            std::unique_ptr<crypto::SecureHash>());
        EXPECT_EQ(expected_error_, result);
        return result == DOWNLOAD_INTERRUPT_REASON_NONE;
    }

    bool AppendDataToFile(const std::string& data)
    {
        EXPECT_EQ(expect_in_progress_, base_file_->in_progress());
        DownloadInterruptReason result = base_file_->AppendDataToFile(data.data(), data.size());
        if (result == DOWNLOAD_INTERRUPT_REASON_NONE)
            EXPECT_TRUE(expect_in_progress_) << " result = " << result;

        EXPECT_EQ(expected_error_, result);
        if (base_file_->in_progress()) {
            expected_data_ += data;
            if (expected_error_ == DOWNLOAD_INTERRUPT_REASON_NONE) {
                EXPECT_EQ(static_cast<int64_t>(expected_data_.size()),
                    base_file_->bytes_so_far());
            }
        }
        return result == DOWNLOAD_INTERRUPT_REASON_NONE;
    }

    void set_expected_data(const std::string& data) { expected_data_ = data; }

    // Helper functions.
    // Create a file.  Returns the complete file path.
    base::FilePath CreateTestFile()
    {
        base::FilePath file_name;
        BaseFile file((net::NetLogWithSource()));

        EXPECT_EQ(
            DOWNLOAD_INTERRUPT_REASON_NONE,
            file.Initialize(base::FilePath(), temp_dir_.GetPath(), base::File(), 0,
                std::string(), std::unique_ptr<crypto::SecureHash>()));
        file_name = file.full_path();
        EXPECT_NE(base::FilePath::StringType(), file_name.value());

        EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
            file.AppendDataToFile(kTestData4, kTestDataLength4));

        // Keep the file from getting deleted when existing_file_name is deleted.
        file.Detach();

        return file_name;
    }

    // Create a file with the specified file name.
    void CreateFileWithName(const base::FilePath& file_name)
    {
        EXPECT_NE(base::FilePath::StringType(), file_name.value());
        BaseFile duplicate_file((net::NetLogWithSource()));
        EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
            duplicate_file.Initialize(file_name, temp_dir_.GetPath(),
                base::File(), 0, std::string(),
                std::unique_ptr<crypto::SecureHash>()));
        // Write something into it.
        duplicate_file.AppendDataToFile(kTestData4, kTestDataLength4);
        // Detach the file so it isn't deleted on destruction of |duplicate_file|.
        duplicate_file.Detach();
    }

    int64_t CurrentSpeedAtTime(base::TimeTicks current_time)
    {
        EXPECT_TRUE(base_file_.get());
        return base_file_->CurrentSpeedAtTime(current_time);
    }

    base::TimeTicks StartTick()
    {
        EXPECT_TRUE(base_file_.get());
        return base_file_->start_tick_;
    }

    void set_expected_error(DownloadInterruptReason err)
    {
        expected_error_ = err;
    }

    void ExpectPermissionError(DownloadInterruptReason err)
    {
        EXPECT_TRUE(err == DOWNLOAD_INTERRUPT_REASON_FILE_TRANSIENT_ERROR || err == DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED)
            << "Interrupt reason = " << err;
    }

    template <size_t SZ>
    static void ExpectHashValue(const uint8_t (&expected_hash)[SZ],
        std::unique_ptr<crypto::SecureHash> hash_state)
    {
        std::vector<uint8_t> hash_value(hash_state->GetHashLength());
        hash_state->Finish(&hash_value.front(), hash_value.size());
        ASSERT_EQ(SZ, hash_value.size());
        EXPECT_EQ(0, memcmp(expected_hash, &hash_value.front(), hash_value.size()));
    }

protected:
    // BaseClass instance we are testing.
    std::unique_ptr<BaseFile> base_file_;

    // Temporary directory for renamed downloads.
    base::ScopedTempDir temp_dir_;

    // Expect the file to survive deletion of the BaseFile instance.
    bool expect_file_survives_;

    // Expect the file to be in progress.
    bool expect_in_progress_;

private:
    // Keep track of what data should be saved to the disk file.
    std::string expected_data_;
    DownloadInterruptReason expected_error_;

    TestBrowserThreadBundle thread_bundle_;
};

// This will initialize the entire array to zero.
const unsigned char BaseFileTest::kEmptySha256Hash[] = { 0 };

// Test the most basic scenario: just create the object and do a sanity check
// on all its accessors. This is actually a case that rarely happens
// in production, where we would at least Initialize it.
TEST_F(BaseFileTest, CreateDestroy)
{
    EXPECT_EQ(base::FilePath().value(), base_file_->full_path().value());
}

// Cancel the download explicitly.
TEST_F(BaseFileTest, Cancel)
{
    ASSERT_TRUE(InitializeFile());
    EXPECT_TRUE(base::PathExists(base_file_->full_path()));
    base_file_->Cancel();
    EXPECT_FALSE(base::PathExists(base_file_->full_path()));
    EXPECT_NE(base::FilePath().value(), base_file_->full_path().value());
}

// Write data to the file and detach it, so it doesn't get deleted
// automatically when base_file_ is destructed.
TEST_F(BaseFileTest, WriteAndDetach)
{
    ASSERT_TRUE(InitializeFile());
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    base_file_->Finish();
    base_file_->Detach();
    expect_file_survives_ = true;
}

// Write data to the file and detach it, and calculate its sha256 hash.
TEST_F(BaseFileTest, WriteWithHashAndDetach)
{
    ASSERT_TRUE(InitializeFile());
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    ExpectHashValue(kHashOfTestData1, base_file_->Finish());
    base_file_->Detach();
    expect_file_survives_ = true;
}

// Rename the file after writing to it, then detach.
TEST_F(BaseFileTest, WriteThenRenameAndDetach)
{
    ASSERT_TRUE(InitializeFile());

    base::FilePath initial_path(base_file_->full_path());
    EXPECT_TRUE(base::PathExists(initial_path));
    base::FilePath new_path(temp_dir_.GetPath().AppendASCII("NewFile"));
    EXPECT_FALSE(base::PathExists(new_path));

    ASSERT_TRUE(AppendDataToFile(kTestData1));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE, base_file_->Rename(new_path));
    EXPECT_FALSE(base::PathExists(initial_path));
    EXPECT_TRUE(base::PathExists(new_path));

    ExpectHashValue(kHashOfTestData1, base_file_->Finish());
    base_file_->Detach();
    expect_file_survives_ = true;
}

// Write data to the file once.
TEST_F(BaseFileTest, SingleWrite)
{
    ASSERT_TRUE(InitializeFile());
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    ExpectHashValue(kHashOfTestData1, base_file_->Finish());
}

// Write data to the file multiple times.
TEST_F(BaseFileTest, MultipleWrites)
{
    ASSERT_TRUE(InitializeFile());
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));
    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Write data to the file multiple times, interrupt it, and continue using
// another file.  Calculate the resulting combined sha256 hash.
TEST_F(BaseFileTest, MultipleWritesInterruptedWithHash)
{
    ASSERT_TRUE(InitializeFile());
    // Write some data
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    // Get the hash state and file name.
    std::unique_ptr<crypto::SecureHash> hash_state = base_file_->Finish();

    base::FilePath new_file_path(temp_dir_.GetPath().Append(
        base::FilePath(FILE_PATH_LITERAL("second_file"))));

    ASSERT_TRUE(base::CopyFile(base_file_->full_path(), new_file_path));

    // Create another file
    BaseFile second_file((net::NetLogWithSource()));
    ASSERT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        second_file.Initialize(new_file_path,
            base::FilePath(),
            base::File(),
            base_file_->bytes_so_far(),
            std::string(),
            std::move(hash_state)));
    std::string data(kTestData3);
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        second_file.AppendDataToFile(data.data(), data.size()));
    ExpectHashValue(kHashOfTestData1To3, second_file.Finish());
}

// Rename the file after all writes to it.
TEST_F(BaseFileTest, WriteThenRename)
{
    ASSERT_TRUE(InitializeFile());

    base::FilePath initial_path(base_file_->full_path());
    EXPECT_TRUE(base::PathExists(initial_path));
    base::FilePath new_path(temp_dir_.GetPath().AppendASCII("NewFile"));
    EXPECT_FALSE(base::PathExists(new_path));

    ASSERT_TRUE(AppendDataToFile(kTestData1));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Rename(new_path));
    EXPECT_FALSE(base::PathExists(initial_path));
    EXPECT_TRUE(base::PathExists(new_path));

    ExpectHashValue(kHashOfTestData1, base_file_->Finish());
}

// Rename the file while the download is still in progress.
TEST_F(BaseFileTest, RenameWhileInProgress)
{
    ASSERT_TRUE(InitializeFile());

    base::FilePath initial_path(base_file_->full_path());
    EXPECT_TRUE(base::PathExists(initial_path));
    base::FilePath new_path(temp_dir_.GetPath().AppendASCII("NewFile"));
    EXPECT_FALSE(base::PathExists(new_path));

    ASSERT_TRUE(AppendDataToFile(kTestData1));

    EXPECT_TRUE(base_file_->in_progress());
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE, base_file_->Rename(new_path));
    EXPECT_FALSE(base::PathExists(initial_path));
    EXPECT_TRUE(base::PathExists(new_path));

    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));

    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Test that a failed rename reports the correct error.
TEST_F(BaseFileTest, RenameWithError)
{
    ASSERT_TRUE(InitializeFile());

    // TestDir is a subdirectory in |temp_dir_| that we will make read-only so
    // that the rename will fail.
    base::FilePath test_dir(temp_dir_.GetPath().AppendASCII("TestDir"));
    ASSERT_TRUE(base::CreateDirectory(test_dir));

    base::FilePath new_path(test_dir.AppendASCII("TestFile"));
    EXPECT_FALSE(base::PathExists(new_path));

    {
        base::FilePermissionRestorer restore_permissions_for(test_dir);
        ASSERT_TRUE(base::MakeFileUnwritable(test_dir));
        ExpectPermissionError(base_file_->Rename(new_path));
    }

    base_file_->Finish();
}

// Test that if a rename fails for an in-progress BaseFile, it remains writeable
// and renameable.
TEST_F(BaseFileTest, RenameWithErrorInProgress)
{
    ASSERT_TRUE(InitializeFile());

    base::FilePath test_dir(temp_dir_.GetPath().AppendASCII("TestDir"));
    ASSERT_TRUE(base::CreateDirectory(test_dir));

    base::FilePath new_path(test_dir.AppendASCII("TestFile"));
    EXPECT_FALSE(base::PathExists(new_path));

    // Write some data to start with.
    ASSERT_TRUE(AppendDataToFile(kTestData1));
    ASSERT_TRUE(base_file_->in_progress());

    base::FilePath old_path = base_file_->full_path();

    {
        base::FilePermissionRestorer restore_permissions_for(test_dir);
        ASSERT_TRUE(base::MakeFileUnwritable(test_dir));
        ExpectPermissionError(base_file_->Rename(new_path));

        // The file should still be open and we should be able to continue writing
        // to it.
        ASSERT_TRUE(base_file_->in_progress());
        ASSERT_TRUE(AppendDataToFile(kTestData2));
        ASSERT_EQ(old_path.value(), base_file_->full_path().value());

        // Try to rename again, just for kicks. It should still fail.
        ExpectPermissionError(base_file_->Rename(new_path));
    }

    // Now that TestDir is writeable again, we should be able to successfully
    // rename the file.
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE, base_file_->Rename(new_path));
    ASSERT_EQ(new_path.value(), base_file_->full_path().value());
    ASSERT_TRUE(AppendDataToFile(kTestData3));

    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Test that a failed write reports an error.
TEST_F(BaseFileTest, WriteWithError)
{
    base::FilePath path;
    ASSERT_TRUE(base::CreateTemporaryFile(&path));

    // Pass a file handle which was opened without the WRITE flag.
    // This should result in an error when writing.
    base::File file(path, base::File::FLAG_OPEN_ALWAYS | base::File::FLAG_READ);
    base_file_.reset(new BaseFile(net::NetLogWithSource()));
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(path, base::FilePath(), std::move(file), 0,
            std::string(),
            std::unique_ptr<crypto::SecureHash>()));
#if defined(OS_WIN)
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED);
#elif defined(OS_POSIX)
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_FAILED);
#endif
    ASSERT_FALSE(AppendDataToFile(kTestData1));
    base_file_->Finish();
}

// Try to write to uninitialized file.
TEST_F(BaseFileTest, UninitializedFile)
{
    expect_in_progress_ = false;
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_FAILED);
    EXPECT_FALSE(AppendDataToFile(kTestData1));
}

// Create two |BaseFile|s with the same file, and attempt to write to both.
// Overwrite base_file_ with another file with the same name and
// non-zero contents, and make sure the last file to close 'wins'.
TEST_F(BaseFileTest, DuplicateBaseFile)
{
    ASSERT_TRUE(InitializeFile());

    // Create another |BaseFile| referring to the file that |base_file_| owns.
    CreateFileWithName(base_file_->full_path());

    ASSERT_TRUE(AppendDataToFile(kTestData1));
    base_file_->Finish();
}

// Create a file and append to it.
TEST_F(BaseFileTest, AppendToBaseFile)
{
    // Create a new file.
    base::FilePath existing_file_name = CreateTestFile();
    set_expected_data(kTestData4);

    // Use the file we've just created.
    base_file_.reset(new BaseFile(net::NetLogWithSource()));
    ASSERT_EQ(
        DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(existing_file_name, base::FilePath(), base::File(),
            kTestDataLength4, std::string(),
            std::unique_ptr<crypto::SecureHash>()));

    const base::FilePath file_name = base_file_->full_path();
    EXPECT_NE(base::FilePath::StringType(), file_name.value());

    // Write into the file.
    EXPECT_TRUE(AppendDataToFile(kTestData1));

    base_file_->Finish();
    base_file_->Detach();
    expect_file_survives_ = true;
}

// Create a read-only file and attempt to write to it.
TEST_F(BaseFileTest, ReadonlyBaseFile)
{
    // Create a new file.
    base::FilePath readonly_file_name = CreateTestFile();

    // Restore permissions to the file when we are done with this test.
    base::FilePermissionRestorer restore_permissions(readonly_file_name);

    // Make it read-only.
    EXPECT_TRUE(base::MakeFileUnwritable(readonly_file_name));

    // Try to overwrite it.
    base_file_.reset(new BaseFile(net::NetLogWithSource()));
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_ACCESS_DENIED,
        base_file_->Initialize(readonly_file_name, base::FilePath(),
            base::File(), 0, std::string(),
            std::unique_ptr<crypto::SecureHash>()));

    expect_in_progress_ = false;

    const base::FilePath file_name = base_file_->full_path();
    EXPECT_NE(base::FilePath::StringType(), file_name.value());

    // Write into the file.
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_FAILED);
    EXPECT_FALSE(AppendDataToFile(kTestData1));

    base_file_->Finish();
    base_file_->Detach();
    expect_file_survives_ = true;
}

// Open an existing file and continue writing to it. The hash of the partial
// file is known and matches the existing contents.
TEST_F(BaseFileTest, ExistingBaseFileKnownHash)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    ASSERT_EQ(kTestDataLength1,
        base::WriteFile(file_path, kTestData1, kTestDataLength1));

    std::string hash_so_far(std::begin(kHashOfTestData1),
        std::end(kHashOfTestData1));
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength1, hash_so_far,
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_data(kTestData1);
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));
    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Open an existing file and continue writing to it. The hash of the partial
// file is unknown.
TEST_F(BaseFileTest, ExistingBaseFileUnknownHash)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    ASSERT_EQ(kTestDataLength1,
        base::WriteFile(file_path, kTestData1, kTestDataLength1));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength1, std::string(),
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_data(kTestData1);
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));
    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Open an existing file. The contentsof the file doesn't match the known hash.
TEST_F(BaseFileTest, ExistingBaseFileIncorrectHash)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    ASSERT_EQ(kTestDataLength2,
        base::WriteFile(file_path, kTestData2, kTestDataLength2));

    std::string hash_so_far(std::begin(kHashOfTestData1),
        std::end(kHashOfTestData1));
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength2, hash_so_far,
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH);
}

// Open a large existing file with a known hash and continue writing to it.
TEST_F(BaseFileTest, ExistingBaseFileLargeSizeKnownHash)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    std::string big_buffer(1024 * 200, 'a');
    ASSERT_EQ(static_cast<int>(big_buffer.size()),
        base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));

    // Hash of partial file (1024*200 * 'a')
    const uint8_t kExpectedPartialHash[] = {
        0x4b, 0x4f, 0x0f, 0x46, 0xac, 0x02, 0xd1, 0x77, 0xde, 0xa0, 0xab,
        0x36, 0xa6, 0x6a, 0x65, 0x78, 0x40, 0xe2, 0xfb, 0x98, 0xb2, 0x0b,
        0xb2, 0x7a, 0x68, 0x8d, 0xb4, 0xd8, 0xea, 0x9c, 0xd2, 0x2c
    };

    // Hash of entire file (1024*400 * 'a')
    const uint8_t kExpectedFullHash[] = {
        0x0c, 0xe9, 0xf6, 0x78, 0x6b, 0x0f, 0x58, 0x49, 0x36, 0xe8, 0x83,
        0xc5, 0x09, 0x16, 0xbc, 0x5e, 0x2d, 0x07, 0x95, 0xb9, 0x42, 0x20,
        0x41, 0x7c, 0xb3, 0x38, 0xd3, 0xf4, 0xe0, 0x78, 0x89, 0x46
    };

    ASSERT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            big_buffer.size(),
            std::string(std::begin(kExpectedPartialHash),
                std::end(kExpectedPartialHash)),
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_data(big_buffer); // Contents of the file on Open.
    ASSERT_TRUE(AppendDataToFile(big_buffer));
    ExpectHashValue(kExpectedFullHash, base_file_->Finish());
}

// Open a large existing file. The contents doesn't match the known hash.
TEST_F(BaseFileTest, ExistingBaseFileLargeSizeIncorrectHash)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    std::string big_buffer(1024 * 200, 'a');
    ASSERT_EQ(static_cast<int>(big_buffer.size()),
        base::WriteFile(file_path, big_buffer.data(), big_buffer.size()));

    // Incorrect hash of partial file (1024*200 * 'a')
    const uint8_t kExpectedPartialHash[] = {
        0xc2, 0xa9, 0x08, 0xd9, 0x8f, 0x5d, 0xf9, 0x87, 0xad, 0xe4, 0x1b,
        0x5f, 0xce, 0x21, 0x30, 0x67, 0xef, 0x6c, 0xc2, 0x1e, 0xf2, 0x24,
        0x02, 0x12, 0xa4, 0x1e, 0x54, 0xb5, 0xe7, 0xc2, 0x8a, 0xe5
    };

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            big_buffer.size(),
            std::string(std::begin(kExpectedPartialHash),
                std::end(kExpectedPartialHash)),
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_HASH_MISMATCH);
}

// Open an existing file. The size of the file is too short.
TEST_F(BaseFileTest, ExistingBaseFileTooShort)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    ASSERT_EQ(kTestDataLength1,
        base::WriteFile(file_path, kTestData1, kTestDataLength1));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength1 + 1, std::string(),
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_error(DOWNLOAD_INTERRUPT_REASON_FILE_TOO_SHORT);
}

// Open an existing file. The size is larger than expected.
TEST_F(BaseFileTest, ExistingBaseFileKnownHashTooLong)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    std::string contents;
    contents.append(kTestData1);
    contents.append("Something extra");
    ASSERT_EQ(static_cast<int>(contents.size()),
        base::WriteFile(file_path, contents.data(), contents.size()));

    std::string hash_so_far(std::begin(kHashOfTestData1),
        std::end(kHashOfTestData1));
    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength1, hash_so_far,
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_data(kTestData1); // Our starting position.
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));
    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Open an existing file. The size is large than expected and the hash is
// unknown.
TEST_F(BaseFileTest, ExistingBaseFileUnknownHashTooLong)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    std::string contents;
    contents.append(kTestData1);
    contents.append("Something extra");
    ASSERT_EQ(static_cast<int>(contents.size()),
        base::WriteFile(file_path, contents.data(), contents.size()));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kTestDataLength1, std::string(),
            std::unique_ptr<crypto::SecureHash>()));
    set_expected_data(kTestData1);
    ASSERT_TRUE(AppendDataToFile(kTestData2));
    ASSERT_TRUE(AppendDataToFile(kTestData3));
    ExpectHashValue(kHashOfTestData1To3, base_file_->Finish());
}

// Similar to ExistingBaseFileKnownHashTooLong test, but with a file large
// enough to requre multiple Read()s to complete. This provides additional code
// coverage for the CalculatePartialHash() logic.
TEST_F(BaseFileTest, ExistingBaseFileUnknownHashTooLongForLargeFile)
{
    base::FilePath file_path = temp_dir_.GetPath().AppendASCII("existing");
    const size_t kFileSize = 1024 * 1024;
    const size_t kIntermediateSize = kFileSize / 2 + 111;
    // |contents| is 100 bytes longer than kIntermediateSize. The latter is the
    // expected size.
    std::string contents(kIntermediateSize + 100, 'a');
    ASSERT_EQ(static_cast<int>(contents.size()),
        base::WriteFile(file_path, contents.data(), contents.size()));

    EXPECT_EQ(DOWNLOAD_INTERRUPT_REASON_NONE,
        base_file_->Initialize(file_path, base::FilePath(), base::File(),
            kIntermediateSize, std::string(),
            std::unique_ptr<crypto::SecureHash>()));
    // The extra bytes should be stripped during Initialize().
    contents.resize(kIntermediateSize, 'a');
    set_expected_data(contents);
    std::string new_data(kFileSize - kIntermediateSize, 'a');
    ASSERT_TRUE(AppendDataToFile(new_data));
    const uint8_t kExpectedHash[] = {
        0x9b,
        0xc1,
        0xb2,
        0xa2,
        0x88,
        0xb2,
        0x6a,
        0xf7,
        0x25,
        0x7a,
        0x36,
        0x27,
        0x7a,
        0xe3,
        0x81,
        0x6a,
        0x7d,
        0x4f,
        0x16,
        0xe8,
        0x9c,
        0x1e,
        0x7e,
        0x77,
        0xd0,
        0xa5,
        0xc4,
        0x8b,
        0xad,
        0x62,
        0xb3,
        0x60,
    };
    ExpectHashValue(kExpectedHash, base_file_->Finish());
}

// Test that a temporary file is created in the default download directory.
TEST_F(BaseFileTest, CreatedInDefaultDirectory)
{
    ASSERT_TRUE(base_file_->full_path().empty());
    ASSERT_TRUE(InitializeFile());
    EXPECT_FALSE(base_file_->full_path().empty());

    // On Windows, CreateTemporaryFileInDir() will cause a path with short names
    // to be expanded into a path with long names. Thus temp_dir.GetPath() might
    // not
    // be a string-wise match to base_file_->full_path().DirName() even though
    // they are in the same directory.
    base::FilePath temp_file;
    ASSERT_TRUE(base::CreateTemporaryFileInDir(temp_dir_.GetPath(), &temp_file));
    ASSERT_FALSE(temp_file.empty());
    EXPECT_STREQ(temp_file.DirName().value().c_str(),
        base_file_->full_path().DirName().value().c_str());
    base_file_->Finish();
}

TEST_F(BaseFileTest, NoDoubleDeleteAfterCancel)
{
    ASSERT_TRUE(InitializeFile());
    base::FilePath full_path = base_file_->full_path();
    ASSERT_FALSE(full_path.empty());
    ASSERT_TRUE(base::PathExists(full_path));

    base_file_->Cancel();
    ASSERT_FALSE(base::PathExists(full_path));

    const char kData[] = "hello";
    const int kDataLength = static_cast<int>(arraysize(kData) - 1);
    ASSERT_EQ(kDataLength, base::WriteFile(full_path, kData, kDataLength));
    // The file that we created here should stick around when the BaseFile is
    // destroyed during TearDown.
    expect_file_survives_ = true;
}

} // namespace content
